TOXOPLASMA IGG & REFLEX AVIDITY

Toxoplasma IgG & Reflex Avidity

What it is

The Toxoplasma IgG & Reflex Avidity test measures IgG antibodies against Toxoplasma gondii, the parasite that causes toxoplasmosis. IgG antibodies indicate past or chronic infection. The reflex avidity test is performed when IgG is positive to determine whether the infection is recent or long-standing by analyzing the strength of antibody binding.

Uses

This test is especially important in pregnant women to distinguish between a recent infection (which may affect the fetus) and an old infection (which usually carries no risk to the baby). It is also used in immunocompromised patients to assess infection status and guide treatment decisions.

Symptoms That May Lead to the Test

Doctors may recommend this test if you have swollen lymph nodes, flu-like symptoms, persistent fever, muscle aches, or eye problems. Pregnant women with abnormal ultrasound findings or suspected exposure to toxoplasmosis are also candidates for this test.

Abnormal Results

Positive IgG with High Avidity: Suggests past infection (usually more than 3–5 months old), unlikely to be a recent infection.

Positive IgG with Low Avidity: Indicates recent infection, often within the last 3 months, which may carry a higher risk in pregnancy.

Negative IgG: No evidence of prior infection. The patient remains susceptible to new infection.

Risks

This is a routine blood test with minimal risks. Possible side effects include mild pain, bruising, or bleeding at the puncture site, and rarely dizziness or infection.